Yubuchi So, Tsukasaki Hirofumi, Sakuda Atsushi, Mori Shigeo, Hayashi Akitoshi, Tatsumisago Masahiro
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University 1-1, Gakuen-cho, Naka-ku Sakai Osaka 599-8531 Japan
Department of Material Science, Graduate School of Engineering, Osaka Prefecture University 1-1, Gakuen-cho, Naka-ku Sakai Osaka 599-8531 Japan.
RSC Adv. 2019 May 8;9(25):14465-14471. doi: 10.1039/c9ra00949c. eCollection 2019 May 7.
Liquid-phase synthesis is a useful technique for preparing argyrodite sulfide-based solid electrolytes, and the synthesis conditions such as heat treatment strongly affect the conductivity. Because the understanding of structural changes reveals crucial information about their properties, it is necessary to evaluate this change during heat treatment to determine the factors that affect the conductivity. In this study, X-ray diffraction measurements and transmission electron microscope observations reveal the effects of heat treatment on the crystallinities and ionic conductivities in the synthesis process of argyrodite electrolytes with tetrahydrofuran and ethanol. The amorphous material is in the main phase when heated at low temperatures below 200 °C and exhibits relatively low conductivities of 2 × 10 S cm despite precipitation of the argyrodite crystals. As the heat treatment temperature increases, the ratio of argyrodite crystals increases, involving nucleation and grain growth, leading to high conductivities of over 10 S cm. It is critical to control the ratio of the amorphous and crystal phases to achieve high conductivities in the synthesis of argyrodite electrolytes liquid-phase processing.
液相合成是制备基于硫银锗矿硫化物的固体电解质的一种有用技术，诸如热处理等合成条件会强烈影响其电导率。由于对结构变化的理解揭示了有关其性质的关键信息，因此有必要在热处理过程中评估这种变化，以确定影响电导率的因素。在本研究中，X射线衍射测量和透射电子显微镜观察揭示了在使用四氢呋喃和乙醇合成硫银锗矿电解质的过程中，热处理对结晶度和离子电导率的影响。当在低于200°C的低温下加热时，非晶态材料处于主要相，并且尽管有硫银锗矿晶体析出，但电导率相对较低，为2×10 S/cm。随着热处理温度的升高，硫银锗矿晶体的比例增加，涉及成核和晶粒生长，导致电导率超过10 S/cm。在硫银锗矿电解质的液相加工合成中，控制非晶相和晶相的比例对于实现高电导率至关重要。
